The Kevin Olsen era — for as long or short as it lasts — began Tuesday at the University of Miami, with all eyes on the shaggy-haired redshirt freshman quarterback and his backup, sophomore Gray Crow.

Both were elevated by one unfortunate play that has fifth-year starter Ryan Williams prepared to undergo surgery Wednesday to repair a badly torn anterior cruciate ligament and other damage to his right knee.

“Being the guy is why I came here to Miami,’’ said Olsen, whose age — 19 — is the same as his jersey number. “It’s a shame that this is how I got to be, maybe, ‘the guy,’ or whatever. I’m going to embrace the break I got. It’s unfortunate for Ryan. I feel awful.’’

Williams tore his ACL during UM’s second closed scrimmage Friday night. He dropped back, then cut on a “play-action sort of bootleg’’ as he headed toward the end zone, explained Crow, also suddenly thrust into the foreground. “He made a wrong cut and that was it.

“I was down, but at the same time realized I needed to step up for Ryan. In a game like football, injuries happen like this, but, sure, it’s real scary. Playing quarterback you’re always one play away, so you always have to be ready.’’

With only one day of practice left Thursday before Saturday’s spring game at Sun Life Stadium, both young men are immersing themselves in every nuance of their position.

“I wouldn’t say I’m nervous or anything like that,’’ said Olsen, a Wayne Hills (N.J.) High four-star athlete who was coached by his father Chris and is the younger brother of former Virginia quarterback Christian and Carolina Panthers tight end Greg, a former Hurricanes star. “I probably shouldn’t be here if I was nervous. I didn’t come here to be the backup. I didn’t come here to sit behind people the whole time.

“This year Ryan was going to be the starter and I was going to be in the backup role. Sometimes in football people get tough breaks. We’ve got to help him move on and we’ve also got to move on as an offense and as a team.’’

Olsen, 6-3 and 210 pounds, chose UM over Wisconsin and was ranked 10th nationally among pro-style quarterbacks by Rivals.com and seventh by 247Sports. He has yet to take a snap in college.

Crow, 20, of Clearwater, is a bit bulkier 6-3, 224-pounder who was a three-star prospect by ESPN, Scout.com and Rivals.com. Last season he completed six of eight passes for 55 yards and a touchdown, with one interception, in two games.

UM coach Al Golden said both performed very well and led an extremely spirited, intense practice Tuesday. The coach said Olsen has been “stepping up in the pocket and keeping his eyes down the field and finding his second and third receivers, which is really good. He was unflappable the other night.’’

Crow, who estimated he took 30 to 40 snaps Tuesday compared to his usual “five to 10 at most,’’ has “a strong arm,’’ Golden said. “We got him on the move a little bit more, so play action, move the pocket with him. He threw some really good balls today.’’

Soon enough, the two will be pushed by incoming freshmen quarterbacks Brad Kaaya of West Hills, Calif., and 6-1, 197-pound Malik Rosier of Mobile, Ala.

Kaaya, 6-4 and 213 pounds, is the more highly touted four-star quarterback who threw for a school-record 3,855 yards and 27 touchdowns last season at Chaminade High.

Golden said both will arrive in Coral Gables in five weeks, and are already studying the playbook. The best man, regardless of age, will earn the starting job.

“There are no rules on starting true freshmen,’’ offensive coordinator James Coley said, noting he “wouldn’t be hesitant’’ to start Kaaya or Rosier if either proves superior to the current Canes.

Olsen said he has “already watched the Louisville [bowl] game from last year a couple times, just trying to get maybe a little jump start.’’ He talks every day to his brothers, who told him his time eventually would come — “maybe a little earlier than everybody expected,’’ he said, “but I’m ready to take on this role.’’

Golden told Olsen he doesn’t have to be Superman. “I need to manage the game, get these guys the ball and take the shots when the shots are there,’’ Olsen said. “If I do all that stuff I think our offense is going to be pretty good.’’